Schmidt took the photograph of Obama smiling Tuesday for a self-portrait along with British Prime Minister David Cameron and Danish Prime Minister Helle Thorning Schmidt, who took the picture with her smartphone.

Although other photos showed First Lady Michelle Obama looking peeved over the display, “in reality just a few seconds earlier the first lady was herself joking with those around her, Cameron and Schmidt included,” the photographer said.

“Her stern look was captured by chance,” he said.

Many in the media, and online, had interpreted that “stern look” to mean disapproval of the president’s lighthearted behavior at a historic occasion. Schmidt addressed that, too.

When the Danish prime minister took out her mobile phone and took a photo of herself smiling with Obama and Cameron, she did so in a celebratory environment, he said.

“All around me in the stadium, South Africans were dancing, singing and laughing to honour their departed leader. It was more like a carnival atmosphere, not at all morbid,” Schmidt said. “The ceremony had already gone on for two hours and would last another two. The atmosphere was totally relaxed — I didn’t see anything shocking in my viewfinder, president of the U.S. or not. We are in Africa.”

Schmidt said he doubts anyone could have “remained totally stony faced” for the entire memorial, especially as thousands of people celebrated in the South African stadium where it took place.

“For me, the behaviour of these leaders in snapping a selfie seems perfectly natural,” he said.